Standalone owners and tuners: Who here gets 30+mpg.
09-21-04, 12:08 PM
#28
Eats, Sleeps, Dreams Rotary
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I have a stock ECU but I found that an intake makes the biggest difference with fuel economy. ~10% improvement on the highway. I've beaten the EPA numbers only once in my life 25mpg @ ~70mph, driving behind trucks. If I drive like a sissy on the highway with a mind for economy I can get ~22mpg consistantly. I have a hard time believing a lot of the numbers that people quote are representitive of what they typically get instead of "best cases".
09-21-04, 12:29 PM
#30
How little fuel you can inject or how lean you can run the car depends on SOOO many factors.
For instance I would think these things would help-
A hot air intake (exposed filter underhood) should help you run leaner w/ out stumbles/surges as the heated intake air will vaporize the injected fuel better.
Similarly, the lower the vapor point of the fuel the leaner you could go (winterized gas).
The better your inj. spray pattern the leaner.
A smaller hooked primary port and rough intake runners should keep fuel in suspension and tumble it into the engine and allow leaner mixes.
I'm sure others can add here.
Stock ECU closed loop fluctuates the mixture as rich as 14.7 and then leaner . This variance is due to following the O2 sensor voltage, but coincidentally helps catylize fuel.
As stated earlier a stand alone can be set to run at any given AF ratio. I would guess one should be able to go under 16:1 on stock port NA. My TII surged when running leaner than this, but it has a terrible set-up as far as being able to run lean.
For instance I would think these things would help-
A hot air intake (exposed filter underhood) should help you run leaner w/ out stumbles/surges as the heated intake air will vaporize the injected fuel better.
Similarly, the lower the vapor point of the fuel the leaner you could go (winterized gas).
The better your inj. spray pattern the leaner.
A smaller hooked primary port and rough intake runners should keep fuel in suspension and tumble it into the engine and allow leaner mixes.
I'm sure others can add here.
Stock ECU closed loop fluctuates the mixture as rich as 14.7 and then leaner . This variance is due to following the O2 sensor voltage, but coincidentally helps catylize fuel.
As stated earlier a stand alone can be set to run at any given AF ratio. I would guess one should be able to go under 16:1 on stock port NA. My TII surged when running leaner than this, but it has a terrible set-up as far as being able to run lean.
10-20-04, 12:06 AM
#32
Full Member
well. i've reall the whole post including the one before this.. and all i have to say is.. " i don't think you are able to get 30 mpg. even with a stand alone.. I'll be lucky if i get 20 mpg on my 10th anni.tII. i'll soon purchase a stand alone.. and even then.. i dont think i'll bet getting more than what im getting now.. lol"
10-20-04, 12:13 AM
#33
I wish I was driving!
Originally Posted by jacobcartmill
anyone?
34 mpg on an 87 GT is my best to date. Aiming for 36 when all is said and done.
10-20-04, 12:33 AM
#34
Lives on the Forum
It's possible to hit 30mpg, but I would question on the high EGT's the engine will see.
Is the gain in gas mileage worth stressing the motors that much?
I can get Haltech's to hit 25mpg to 28mpg pretty easily.
-Ted
Is the gain in gas mileage worth stressing the motors that much?
I can get Haltech's to hit 25mpg to 28mpg pretty easily.
-Ted
10-20-04, 02:08 AM
#36
One thing I learned when doing some highway runs - windows & sunroof make a huge difference. I get 22mpg or so with the windows & sunroof open, and closer to 25-26 with them up.
All I have mod-wise are pineapple inserts (not an issue for fuel economy normally) and a RB presilencer/cat replacement pipe.
-=Russ=-
All I have mod-wise are pineapple inserts (not an issue for fuel economy normally) and a RB presilencer/cat replacement pipe.
-=Russ=-
10-20-04, 02:13 AM
#37
Rotorphile.
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I get an average of 25mpg on a stock ECU and an untuned S-AFR (which reminds me, I need to tune that bugger) on a high milage S4 N/A engine. This isn't taking into account the oversized rear tires, either... still, if I lean out the 3k RPM/80mph band I normally cruise in I can probably see 27mpg actual.
I can only dream of a standalone though, I would think it would be easy to pull off 30mpg N/A and not even worry about A/F ratios.
I can only dream of a standalone though, I would think it would be easy to pull off 30mpg N/A and not even worry about A/F ratios.
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